C Standard Library Functions

FreeBASIC

This is a list of function prototypes in the standard C library in alphabetical order and a list of prototypes grouped by functionality.

Alphabetical List
Buffer Manipulation
Character Classification and Conversion
Data Conversion
Directory Manipulation
File Manipulation
Stream I/O
Low level I/O
Mathematics
Memory Allocation
Process Control
Searching and Sorting
String Manipulation
Time

Description

The Comments column contains a very brief description of the use of the function. The list is not complete, however it provides information on the major functions in the C Runtime Library. It should, at the very least, indicate what functions are available in the standard C library allow you to do more investigation on your own. Some of the C library functions documented elsewhere may not be available in FreeBASIC. Check the appropriate include file for more information.

Note: The following prototypes are not the official FreeBASIC prototypes (see the include files), however, they will give you enough information to properly use the functions.

The Include File column contains the name of the file which you must include, using the #include directive at the beginning of your program. If you don't include the appropriate include file, the program either will not compile, or it will compile apparently correctly but give incorrect results when run. All of the C Runtime headers are located in the crt directory; for example, if the specified header is math.bi, use #include "crt/math.bi" or #include "crt\math.bi", our just #include "crt.bi" including all the others.

The Prototype column contains the following information:

The name of the function;
The parameters required for the function in parenthesis, together with the data-type of the parameters;
The data-type of the value returned by the function.

For example atoi(a as zstring ptr) as integer means that the function atoi returns a value of type integer and requires a character zstring ptr as its argument.

Note: In order to make calling the C runtime functions very easy, any string type argument may be directly passed to a procedure referring to a parameter declared as 'zstring ptr'. The compiler performs itself an automatic conversion (without warning message) between string and 'zstring ptr'.

Alphabetical List

Name	Prototype (with parameters)	Include File	Comments
abs_	abs_(n as integer) as integer	stdlib.bi	Returns the absolute value (i.e. positive value)
acos_	acos_(a as double) as double	math.bi	Returns the inverse cosine (angle in radians)
asin_	asin_(a as double) as double	math.bi	Returns the inverse sine (angle in radians)
atan_	atan_(a as double) as double	math.bi	Returns the inverse tan (angle in radians)
atan2_	atan2_(y as double, x as double) as double	math.bi	Returns the inverse tan (pass the opposite as y and the adjacent as x)
atoi	atoi(s as zstring ptr) as integer	stdlib.bi	Converts a character zstring of digits to a number of type integer.
atof	atof(s as zstring ptr) as double	stdlib.bi	Converts a character zstring of digits to a number of type double.
calloc	calloc(NumElts as integer, EltSiz as integer) as any ptr	stdlib.bi	Allocates memory. Returns a pointer to a buffer for an array having NumElts elements, each of size EltSiz bytes.
ceil	ceil(d as double) as double	math.bi	Returns the nearest whole number above the value passed.
clearerr	clearerr(s as FILE ptr)	stdio.bi	Clears the error indicators on a file stream (read or write).
cos_	cos_(ar as double) as double	math.bi	Returns the cosine of an angle measured in radians.
cosh	cosh(x as double) as double	math.bi	Returns the hyperbolic cosine of an angle measured in radians.
div	div(num as integer, denom as integer) as div_t	stdlib.bi	Returns the quotient and remainder of a division as a structure of type div_t.
ecvt	ecvt(x as double) as zstring ptr	math.bi	Converts a number to a zstring.
exit_	exit_(status as integer)	stdlib.bi	Exits a program. It will flush file buffers and closes all opened files, and run any functions called by atexit().
exp_	exp_(a as double) as double	math.bi	Returns the value of e raised to the power of the argument (Inverse to natural logarithm).
fabs	fabs(d as double) as double	math.bi	Returns the absolute value (i.e. positive value) of type double.
fclose	fclose(s as FILE ptr) as FILE ptr	stdio.bi	Closes a file. Returns 0 if successful otherwise EOF.
feof	feof(s as FILE ptr) as integer	stdio.bi	Returns value of end-of-file indicator . (0 if not eof). Indicator will clear itself but can be reset by clearerr().
ferror	ferror(s as FILE ptr) as integer	stdio.bi	Returns error indicator for a stream (0 if no error). Error indicator is reset by clearerr() or rewind().
fflush	fflush(s as FILE ptr) as integer	stdio.bi	Flushes (i.e. deletes) a stream (use stdin to flush the stream from the keyboard). Returns 0 if successful.
fgetc	fgetc(s as FILE ptr) as integer	stdio.bi	Single character input (in ASCII) from passed stream (stdin for keyboard).
fgetpos	fgetpos(s as FILE ptr, c as fpos_t ptr) as integer	stdio.bi	Saves the position of the file pointer on stream s at the location pointed to by c.
fgets	fgets(b as zstring ptr, n as integer, s as FILE ptr) as zstring ptr	stdio.bi	From the stream s reads up to n-1 characters to buffer b.
floor	floor(d as double) as double	math.bi	Returns the nearest whole number below the value passed.
fmod	fmod(x as double, y as double) as double	math.bi	Calculates the remainder of x divided by y.
fopen	fopen(file as zstring ptr, mode as zstring ptr) as FILE ptr	stdio.bi	Opens a file. Pass the DOS name of the file and a code to indicate whether for reading, writing, or appending. Codes are r for read, w for write, + for read and write, a for append and b to indicate binary.
fprintf	fprintf(s as FILE ptr, fmt as zstring ptr, ...) as integer	stdio.bi	Prints on stream s as many items as there are single % signs in fmt that have matching arguments in the list.
fputc	fputc(c as integer, s as FILE ptr) as integer	stdio.bi	Outputs the single character c to the stream s.
fputs	fputs(b as zstring ptr, s as FILE ptr) as integer	stdio.bi	Sends the character stream in b to stream s, returns 0 if the operation fails.
fread	fread(buf as any ptr, b as size_t, c as size_t, s as FILE ptr) as integer	stdio.bi	Reads the number c items of data of size b bytes from file s to the buffer buf. Returns the number of data items actually read.
free	free(p as any ptr)	stdlib.bi	Frees the memory allocation for a pointer p to enable this memory to be used.
freopen	freopen(file as zstring ptr, mode as zstring ptr, s as FILE ptr) as FILE ptr	stdio.bi	Opens a file for redirecting a stream. e.g. freopen("myfile", "w", stdout) will redirect the standard output to the opened "myfile".
frexp	frexp(x as double, p as integer ptr) as double	math.bi	Calculates a value m so that x equals m times 2 to some power. p is a pointer to m.
fscanf	fscanf(s as FILE ptr, fmt as zstring ptr, ...) as integer	stdio.bi	Reads from stream s as many items as there are % signs in fmt with corresponding listed pointers.
fseek	fseek(s as FILE ptr, offset as integer, origin as integer) as integer	stdio.bi	Locates a file pointer. With origin 0, 1 or 2 for the beginning, offset bytes into and at the end of the stream.
fsetpos	fsetpos(s as FILE ptr, p as fpos_t ptr) as integer	stdio.bi	Sets the file pointer for the stream s to the value pointed to by p.
ftell	ftell(s as FILE ptr) as long	stdio.bi	Locates the position of the file pointer for the stream s.
fwrite	fwrite(buf as any ptr, b as integer, c as integer, s as FILE ptr) as integer	stdio.bi	Writes the number c items of data of size b bytes from the buffer buf to the file s. Returns the number of data items actually written.
getc	getc(s as FILE ptr) as integer	stdio.bi	Macro for single character input (in ASCII) from passed stream. (stdin for keyboard)
getchar	getchar() as integer	stdio.bi	Single character input from the standard input
gets	gets(b as zstring ptr) as zstring ptr	stdio.bi	Reads a stream of characters from the standard input until it meets \n or EOF.
hypot	hypot(x as double, y as double) as double	math.bi	Calculates the hypotenuse from the sides x and y.
isalnum	isalnum(c as integer) as integer	ctype.bi	Returns a non zero value if character c is alphabetic or a digit.
isalpha	isalpha(c as integer) as integer	ctype.bi	Returns a non zero value if character c is alphabetic.
iscntrl	iscntrl(c as integer) as integer	ctype.bi	Returns a non zero value if character c is a control character.
isdigit	isdigit(c as integer) as integer	ctype.bi	Returns a non zero value if character c is a digit.
isgraph	isgraph(c as integer) as integer	ctype.bi	Returns a non zero value if character c is alphabetic.
islower	islower(c as integer) as integer	ctype.bi	Returns a non-zero value if character c is a lower case character.
isprint	isprint(c as integer) as integer	ctype.bi	Returns a non zero value if character c is printable.
ispunct	ispunct(c as integer) as integer	ctype.bi	Returns a non zero value if character c is a punctuation character.
isspace	isspace(c as integer) as integer	ctype.bi	Returns a non zero value if character c denotes a space.
isupper	isupper(c as integer) as integer	ctype.bi	Returns a non-zero value if character c is an upper case character.
isxdigit	isxdigit(c as integer) as integer	ctype.bi	Returns a non-zero value if character c is a hex digit (0 to F or f).
ldexp	ldexp(x as double, n as integer) as double	math.bi	Returns the product of x and 2 to the power n.
ldiv	ldiv(num as long, denom as long) as ldiv_t	stdlib.bi	Returns the quotient and remainder of a division as a structure of type ldiv_t.
log_	log_(a as double) as double	math.bi	Returns the natural logarithm of the argument.
log10	log10(a as double) as double	math.bi	Returns the logarithm to the base 10 of the argument.
malloc	malloc(bytes as integer) as any ptr	stdlib.bi	Allocates memory. Returns a pointer to a buffer comprising storage for the specified size.
modf	modf(d as double, p as double ptr) as double	math.bi	Returns the fractional part of a floating point number d. p points to the integral part expressed as a float.
perror	perror(mess as zstring ptr)	stdio.bi	Prints on the stream stderr a message passed as the argument.
pow	pow(x as double, y as double) as double	math.bi	Returns x to the power y.
pow10	pow10(x as double) as double	math.bi	Returns 10 to the power x (inverse function to log10()).
printf	printf(fmt as zstring ptr, ...) as integer	stdio.bi	Prints on standard output as many items as there are single % signs in fmt with matching arguments in the list.
putc	putc(c as integer, s as FILE ptr) as integer	stdio.bi	Macro to output the single character c to the stream s.
putchar	putchar(c as integer) as integer	stdio.bi	Macro to output the single character c to the standard output.
puts	puts(b as zstring ptr) as integer	stdio.bi	Sends the character stream in b to the standard output, returns 0 if operation fails.
rand	rand() as integer	stdlib.bi	Returns a pseudo random number. A seed is required. The seed is set with srand.
realloc	realloc(p as any ptr, newsize as size_t) as any ptr	stdlib.bi	Allocates memory. Returns a pointer to a buffer for a change in size of object pointed to by p.
rewind	rewind(s as FILE ptr)	stdio.bi	Clears the error indicators on a file stream (read or write). Necessary before reading an amended file.
scanf	scanf(fmt as zstring ptr, ...) as integer	stdio.bi	Reads from standard input as many items as there are % signs in fmt with corresponding listed pointers.
sin_	sin_(ar as double) as double	math.bi	Returns the sine of an angle measured in radians.
sinh	sinh(x as double) as double	math.bi	Returns the hyperbolic sine of an angle measured in radians.
sprintf	sprintf(p as zstring ptr, fmt as zstring ptr, ...) as integer	stdio.bi	Prints on zstring p as many items as there are single % signs in fmt that have matching arguments in the list.
sqrt	sqrt(a as double) as double	math.bi	Returns the square root of the value passed. Domain error if value is negative.
srand	srand(seed as uinteger)	stdlib.bi	Sets the seed for a random number. A possible seed is the current time.
sscanf	sscanf(b as zstring ptr, fmt as zstring ptr, ...) as integer	stdio.bi	Reads from buffer b as many items as there are % signs in fmt with corresponding listed pointers.
strcat	strcat(s1 as zstring ptr, s2 as zstring ptr) as zstring ptr	string.bi	Concatenates (appends) zstring s2 to s1.
strchr	strchr(s as zstring ptr, c as integer) as zstring ptr	string.bi	Returns a pointer to the first occurrence of c in s or NULL if it fails to find one.
strcmp	strcmp(s1 as zstring ptr, s2 as zstring ptr) as integer	string.bi	Compares zstring s2 to s1. Returns 0 or signed difference in ASCII values of first non matching character.
strcpy	strcpy(s1 as zstring ptr, s2 as zstring ptr) as zstring ptr	string.bi	Copies s2 into s1.
strcspn	strcspn(s1 as zstring ptr, s2 as zstring ptr) as integer	string.bi	Returns the number of characters in s1 encountered before meeting any of the characters in s2.
strerror	strerror(n as integer) as zstring ptr	string.bi	Returns a pointer to a system error message corresponding to the passed error number.
strlen	strlen(s as zstring ptr) as integer	string.bi	Returns the number of bytes in the null terminated zstring pointed to by s (does not count null).
strncat	strncat(s1 as zstring ptr, s2 as zstring ptr, n as integer) as zstring ptr	string.bi	Concatenates (appends) n bytes from zstring s2 to s1.
strncmp	strncmp(s1 as zstring ptr, s2 as any ptr, n as integer) as integer	string.bi	Compares n bytes of zstring s2 to the same of s1. Returns 0 or signed difference in ASCII values of first non matching character.
strncpy	strncpy(s1 as zstring ptr, s2 as zstring ptr, n as integer) as zstring ptr	string.bi	Copies n bytes from s2 into s1.
strpbrk	strpbrk(s1 as zstring ptr, s2 as zstring ptr) as zstring ptr	string.bi	Returns a pointer to the first character encountered in s1 that is also in s2.
strrchr	strrchr(s as zstring ptr, c as integer) as zstring ptr	string.bi	Returns a pointer to the last occurrence of c in s or NULL if it fails to find one.
strspn	strspn(s1 as zstring ptr, s2 as zstring ptr) as integer	string.bi	Returns the number of characters in s1 encountered before meeting a character which is not in s2.
strstr	strstr(s1 as zstring ptr, s2 as zstring ptr) as zstring ptr	string.bi	Finds the location of the zstring s2 in s1 and returns a pointer to its leading character.
strtod	strtod(s as zstring ptr, p as zstring ptr) as double	stdlib.bi	Converts a zstring to double, provided the zstring is written in the form of a number.
strtok	strtok(s1 as zstring ptr, s2 as zstring ptr) as zstring ptr	string.bi	Returns pointers to successive tokens utilizing the zstring s1. Tokens regarded as separators are listed in s2.
system	system(command as zstring ptr) as integer	stdlib.bi	Executes, from within a program, a command addressed to the operating system written as a zstring (e.g. DIR on Windows and DOS and LS on Linux).
tan_	tan_(ar as double) as double	math.bi	Returns the tangent of an angle measured in radians.
tanh	tanh(x as double) as double	math.bi	Returns the hyperbolic tangent of an angle measured in radians.
tolower	tolower(c as integer) as integer	ctype.bi	Converts a character from upper case to lower case (uses ASCII code).
toupper	toupper(c as integer) as integer	ctype.bi	Converts a character from lower case to upper case (uses ASCII code).
ungetc	ungetc(c as integer, s as FILE ptr) as integer	stdio.bi	Pushes a character c back into the stream s, returns EOF if unsuccessful. Do not push more than one character.

Buffer Manipulation

#include "crt/string.bi"

Prototype (with parameters)	Comments
memchr(s as any ptr, c as integer, n as size_t) as any ptr	Search for a character in a buffer.
memcmp(s1 as any ptr, s2 as any ptr, n as size_t) as integer	Compare two buffers.
memcpy(dest as any ptr, src as any ptr, n as size_t) as any ptr	Copy one buffer into another .
memmove(dest as any ptr, src as any ptr, n as size_t) as any ptr	Move a number of bytes from one buffer lo another.
memset(s as any ptr, c as integer, n as size_t) as any ptr	Set all bytes of a buffer to a given character.

Character Classification and Conversion

#include "crt/ctype.bi"

Prototype (with parameters)	Comments
isalnum(c as integer) as integer	True if c is alphanumeric.
isalpha(c as integer) as integer	True if c is a letter.
isascii(c as integer) as integer	True if c is ASCII .
iscntrl(c as integer) as integer	True if c is a control character.
isdigit(c as integer) as integer	True if c is a decimal digit.
isgraph(c as integer) as integer	True if c is a graphical character.
islower(c as integer) as integer	True if c is a lowercase letter.
isprint(c as integer) as integer	True if c is a printable character.
ispunct(c as integer) as integer	True if c is a punctuation character.
isspace(c as integer) as integer	True if c is a space character.
isupper(c as integer) as integer	True if c is an uppercase letter.
isxdigit(c as integer) as integer	True if c is a hexadecimal digit.
toascii(c as integer) as integer	Convert c to ASCII .
tolower(c as integer) as integer	Convert c to lowercase.
toupper(c as integer) as integer	Convert c to uppercase.

Data Conversion

#include "crt/stdlib.bi"

Prototype (with parameters)	Comments
atof(string1 as zstring ptr) as double	Convert zstring to floating point value.
atoi(string1 as zstring ptr) as integer	Convert zstring to an integer value.
atol(string1 as zstring ptr) as integer	Convert zstring to a long integer value.
itoa(value as integer, zstring as zstring ptr, radix as integer) as zstring ptr	Convert an integer value to a zstring using given radix.
ltoa(value as long, zstring as zstring ptr, radix as integer) as zstring ptr	Convert long integer to zstring in a given radix.
strtod(string1 as zstring ptr, endptr as zstring ptr) as double	Convert zstring to a floating point value.
strtol(string1 as zstring ptr, endptr as zstring ptr, radix as integer) as long	Convert zstring to a long integer using a given radix.
strtoul(string1 as zstring ptr, endptr as zstring ptr, radix as integer) as ulong	Convert zstring to unsigned long.

Directory Manipulation

#include "crt/io.bi"

Prototype (with parameters)	Comments
_chdir(path as zstring ptr) as integer	Change current directory to given path.
_getcwd(path as zstring ptr, numchars as integer) as zstring ptr	Returns name of current working directory.
_mkdir(path as zstring ptr) as integer	Create a directory using given path name.
_rmdir(path as zstring ptr) as integer	Delete a specified directory.

File Manipulation

#include "crt/sys/stat.bi"
#include "crt/io.bi"

Prototype (with parameters)	Comments
chmod(path as zstring ptr, pmode as integer) as integer	Change permission settings of a file.
fstat(handle as integer, buffer as type stat ptr) as integer	Get file status information.
remove(path as zstring ptr) as integer	Delete a named file.
rename_(oldname as zstring ptr, newname as zstring ptr) as integer	rename a file.
stat(path as zstring ptr, buffer as type stat ptr) as integer	Get file status information of named file.
umask(pmode as uinteger) as uinteger	Set file permission mask.

Stream I/O

#include "crt/stdio.bi"

Prototype (with parameters)	Comments
clearerr(file_pointer as FILE ptr)	Clear error indicator of stream,
fclose(file_pointer as FILE ptr) as integer	Close a file,
feof(file_pointer as FILE ptr) as integer	Check if end of file occurred on a stream.
ferror(file_pointer as FILE ptr) as integer	Check if any error occurred during file I/0.
fflush(file_pointer as FILE ptr) as integer	Write out (flush) buffer to file.
fgetc(file_pointer as FILE ptr) as integer	Get a character from a stream.
fgetpos(file_pointer as FILE ptr, fpos_t current_pos) as integer	Get the current position in a stream.
fgets(string1 as zstring ptr, maxchar as integer, file_pointer as FILE ptr) as zstring ptr	Read a zstring from a file.
fopen(filename as zstring ptr, access_mode as zstring ptr) as FILE ptr	Open a file for buffered I/0.
fprintf(file_pointer as FILE ptr, format_string as zstring ptr, args) as integer	Write formatted output to a file,
fputc(c as integer, file_pointer as FILE ptr) as integer	Write a character to a stream.
fputchar(c as integer) as integer	Write a character to stdout.
fputs(string1 as zstring ptr, file_pointer as FILE ptr) as integer	Write a zstring to a stream.
fread(buffer as zstring ptr, size as size_t count as size_t, file_pointer as FILE ptr) as size_t	Read unformatted data from a stream into a buffer.
freopen(filename as zstring ptr, access as zstring ptr mode, file_pointer as FILE ptr) as FILE ptr	Reassign a file pointer to a different file.
fscanf(file_pointer as FILE ptr, format as zstring ptr zstring, args) as integer	Read formatted input from a stream.
fseek(file_pointer as FILE ptr, offset as long, origin as integer) as integer	Set current position in file to a new location.
fsetpos(file_pointer as FILE ptr, current_pos as fpos_t) as integer	Set current position in file to a new location.
ftell(file_pointer as FILE ptr) as long	Get current location in file.
fwrite(buffer as zstring ptr, size as size_t, count as size_t file_pointer as FILE ptr) as size_t	Write unformatted data from a buffer to a stream.
getc(file_pointer as FILE ptr) as integer	Read a character from a stream.
getchar() as integer	Read a character from stdin.
gets(buffer as zstring ptr) as zstring ptr	Read a line from stdin into a buffer.
printf(format as zstring ptr _string, args) as integer	Write formatted output to stdout.
putc(c as integer, file_pointer as FILE ptr) as integer	Write a character to a stream.
putchar(c as integer) as integer	Write a character to stdout.
puts(string1 as zstring ptr) as integer	Write a zstring to stdout.
rewind(file_pointer as FILE ptr)	Rewind a file.
scanf(format_string as zstring ptr, args) as integer	Read formatted input from stdin.
setbuf(file_pointer as FILE ptr, buffer as zstring ptr)	Set up a new buffer for the stream.
setvbuf(file_pointer as FILE ptr, buffer as zstring ptr, buf_type as integer, buf as size_t size) as integer	Set up new buffer and control the level of buffering on a stream.
sprintf(string1 as zstring ptr, format_string as zstring ptr, args) as integer	Write formatted output to a zstring.
sscanf(buffer as zstring ptr, format_string as zstring ptr, args) as integer	Read formatted input from a zstring.
tmpfile() as FILE ptr	Open a temporary file.
tmpnam(file_name as zstring ptr) as zstring ptr	Get temporary file name.
ungetc(c as integer, file_pointer as FILE ptr) as integer	Push back character into stream' s buffer

Low level I/O

#include "crt/io.bi"

So far Win32 only, connects to MSVCRT.DLL (headers missing for other platforms)

Prototype (with parameters)	Comments
_close(handle as integer) as integer	Close a file opened for unbuffered I/O.
_creat(filename as zstring ptr, pmode as integer) as integer	Create a new file with specified permission setting.
_eof(handle as integer) as integer	Check for end of file.
_lseek(handle as integer, offset as long, origin as integer) as long	Go to a specific position in a file.
_open(filename as zstring ptr, oflag as integer, pmode as uinteger) as integer	Open a file for low-level I/O.
_read(handle as integer, buffer as zstring ptr, length as uinteger) as integer	Read binary data from a file into a buffer.
_write(handle as integer, buffer as zstring ptr, count as uinteger) as integer	Write binary data from a buffer to a file.

Mathematics

#include "crt/math.bi"

Prototype (with parameters)	Comments
abs_(n as integer) as integer	Get absolute value of an integer.
acos_(x as double) as double	Compute arc cosine of x.
asin_(x as double) as double	Compute arc sine of x.
atan_(x as double) as double	Compute arc tangent of x.
atan2_(y as double, x as double) as double	Compute arc tangent of y/x.
ceil(x as double) as double	Get smallest integral value that exceeds x.
cos_(x as double) as double	Compute cosine of angle in radians.
cosh(x as double) as double	Compute the hyperbolic cosine of x.
div(number as integer, denom as integer) as div_t	Divide one integer by another.
exp_(x as double) as double	Compute exponential of x.
fabs(x as double) as double	Compute absolute value of x.
floor(x as double) as double	Get largest integral value less than x.
fmod(x as double, y as double) as double	Divide x by y with integral quotient and return remainder.
frexp(x as double, expptr as integer ptr) as double	Breaks down x into mantissa and exponent of no.
labs(n as long) as long	Find absolute value of long integer n.
ldexp(x as double, exp as integer) as double	Reconstructs x out of mantissa and exponent of two.
ldiv(number as long, denom as long) as ldiv_t	Divide one long integer by another.
log_(x as double) as double	Compute log(x).
log10(x as double) as double	Compute log to the base 10 of x.
modf(x as double, intptr as double ptr) as double	Breaks x into fractional and integer parts.
pow(x as double, y as double) as double	Compute x raised to the power y.
rand() as integer	Get a random integer between 0 and 32767.
random(max_num as integer) as integer	Get a random integer between 0 and max_num.
randomize()	Set a random seed for the random number generator.
sin_(x as double) as double	Compute sine of angle in radians.
sinh(x as double) as double	Compute the hyperbolic sine of x.
sqrt(x as double) as double	Compute the square root of x.
srand(seed as uinteger)	Set a new seed for the random number generator (rand).
tan_(x as double) as double	Compute tangent of angle in radians.
tanh(x as double) as double	Compute the hyperbolic tangent of x.

Memory Allocation

#include "crt/stdlib.bi"

Prototype (with parameters)	Comments
calloc(num as size_t elems, elem_size as size_t) as any ptr	Allocate an array and initialise all elements to zero .
free(mem_address as any ptr)	Free a block of memory.
malloc(num as size_t bytes) as any ptr	Allocate a block of memory.
realloc(mem_address as any ptr, newsize as size_t) as any ptr	Reallocate (adjust size) a block of memory.

Process Control

#include "crt/stdlib.bi"

Prototype (with parameters)	Comments
abort()	Abort a process.
execl(path as zstring ptr, arg0 as zstring ptr, arg1 as zstring ptr,..., NULL) as integer	Launch a child process (pass command line).
execlp(path as zstring ptr, arg0 as zstring ptr, arg1 as zstring ptr,..., NULL) as integer	Launch child (use PATH, pass command line).
execv(path as zstring ptr, argv as zstring ptr) as integer	Launch child (pass argument vector).
execvp(path as zstring ptr, argv as zstring ptr) as integer	Launch child (use PATH, pass argument vector).
exit_(status as integer)	Terminate process after flushing all buffers.
getenv(varname as zstring ptr) as zstring ptr	Get definition of environment variable,
perror(string1 as zstring ptr)	Print error message corresponding to last system error.
putenv(envstring as zstring ptr) as integer	Insert new definition into environment table.
raise(signum as integer) as integer	Generate a C signal (exception).
system_(string1 as zstring ptr) as integer	Execute a resident operating system command.

Searching and Sorting

#include "crt/stdlib.bi"

Note: The compare callback function required by bsearch and qsort must be declared as cdecl. It must return a value <0 if its first argument should be located before the second one in the sorted array, >0 if the first argument should be located after the second one, and zero if their relative positions are indifferent (equal values).

Prototype (with parameters)	Comments
bsearch(key as any ptr, base as any ptr, num as size_t, width as size_t, compare as function(elem1 as any ptr, elem2 as any ptr) as integer) as any ptr	Perform binary search.
qsort(base as any ptr, num as size_t, width as size_t, compare as function(elem1 as any ptr, elem2 as any ptr) as integer)	Use the quicksort algorithm to sort an array.

String Manipulation

#include "crt/string.bi"

Prototype (with parameters)	Comments
stpcpy(dest as zstring ptr, src as zstring ptr) as zstring ptr	Copy one zstring into another.
strcmp(string1 as zstring ptr, string2 as zstring ptr) as integer	Compare string1 and string2 to determine alphabetic order.
strcpy(string1 as zstring ptr, string2 as zstring ptr) as zstring ptr	Copy string2 to string1.
strerror(errnum as integer) as zstring ptr	Get error message corresponding to specified error number.
strlen(string1 as zstring ptr) as integer	Determine the length of a zstring.
strncat(string1 as zstring ptr, string2 as zstring ptr, n as size_t) as zstring ptr	Append n characters from string2 to string1.
strncmp(string1 as zstring ptr, string2 as zstring ptr, n as size_t) as integer	Compare first n characters of two strings.
strncpy(string1 as zstring ptr, string2 as zstring ptr, n as size_t) as zstring ptr	Copy first n characters of string2 to string1.
strnset(string1 as zstring ptr, c as integer, size _t n) as zstring ptr	Set first n characters of zstring to c.
strrchr(string1 as zstring ptr, c as integer) as zstring ptr	Find last occurrence of character c in zstring.

Time

#include "crt/time.bi"

Prototype (with parameters)	Comments
asctime(time as type tm ptr) as zstring ptr	Convert time from type tm to zstring.
clock() as clock_t	Get elapsed processor time in clock ticks.
ctime(time as time_t ptr) as zstring ptr	Convert binary time to zstring.
difftime(time_t time2, time_t time1) as double	Compute the difference between two times in seconds.
gmtime(time as time_t ptr) as type tm ptr	Get Greenwich Mean Time (GMT) in a tm structure.
localtime(time as time_t ptr) as type tm ptr	Get the local time in a tm structure.
time_(timeptr as time_t ptr) as time_t	Get current time as seconds elapsed since 0 hours GMT 1/1/70.