| #,
## |
manipulate strings |
| #define |
define variables |
| #error |
display an error message |
| #if,
#ifdef, #ifndef, #else, #elif, #endif |
conditional operators |
| #include |
insert the contents of another
file |
| #line |
set line and file information |
| #pragma |
implementation specific command |
| #undef |
used to undefine variables |
| Predefined
preprocessor variables |
miscellaneous preprocessor
variables |
| abort |
stops the program |
| abs |
absolute value |
| acos |
arc cosine |
| asctime |
a textual version of the time |
| asin |
arc sine |
| assert |
stops the program if an expression isn't
true |
| atan |
arc tangent |
| atan2 |
arc tangent, using signs to determine
quadrants |
| atexit |
sets a function to be called when the
program exits |
| atof |
converts a string to a double |
| atoi |
converts a string to an integer |
| atol |
converts a string to a long |
| bsearch |
perform a binary search |
| calloc |
allocates and clears a two-dimensional
chunk of memory |
| ceil |
the smallest integer not less than a
certain value |
| clearerr |
clears errors |
| clock |
returns the amount of time that the
program has been running |
| cos |
cosine |
| cosh |
hyperbolic cosine |
| ctime |
returns a specifically formatted version
of the time |
| difftime |
the difference between two times |
| div |
returns the quotient and remainder of a
division |
| exit |
stop the program |
| exp |
returns "e" raised to a given
power |
| fabs |
absolute value for floating-point
numbers |
| fclose |
close a file |
| feof |
true if at the end-of-file |
| ferror |
checks for a file error |
| fflush |
writes the contents of the output
buffer |
| fgetc |
get a character from a stream |
| fgetpos |
get the file position indicator |
| fgets |
get a string of characters from a
stream |
| floor |
returns the largest integer not greater
than a given value |
| fmod |
returns the remainder of a
division |
| fopen |
open a file |
| fprintf |
print formatted output to a file |
| fputc |
write a character to a file |
| fputs |
write a string to a file |
| fread |
read from a file |
| free |
returns previously allocated memory to
the operating system |
| freopen |
open an existing stream with a different
name |
| frexp |
decomposes a number into scientific
notation |
| fscanf |
read formatted input from a file |
| fseek |
move to a specific location in a
file |
| fsetpos |
move to a specific location in a
file |
| ftell |
returns the current file position
indicator |
| fwrite |
write to a file |
| getc |
read a character from a file |
| getchar |
read a character from
STDIN |
| getenv |
get enviornment information about a
variable |
| gets |
read a string from
STDIN |
| gmtime |
returns a pointer to the current
Greenwich Mean Time |
| isalnum |
true if a character is
alphanumeric |
| isalpha |
true if a character is alphabetic |
| iscntrl |
true if a character is a control
character |
| isdigit |
true if a character is a digit |
| isgraph |
true if a character is a graphical
character |
| islower |
true if a character is lowercase |
| isprint |
true if a character is a printing
character |
| ispunct |
true if a character is punctuation |
| isspace |
true if a character is a space
character |
| isupper |
true if a character is an uppercase
character |
| isxdigit |
true if a character is a hexidecimal
character |
| labs |
absolute value for long integers |
| ldexp |
computes a number in scientific
notation |
| ldiv |
returns the quotient and remainder of a
division, in long integer form |
| localtime |
returns a pointer to the current
time |
| log |
natural logarithm |
| log10 |
natural logarithm, in base 10 |
| longjmp |
start execution at a certain point in
the program |
| malloc |
allocates memory |
| memchr |
searches an array for the first
occurance of a character |
| memcmp |
compares two buffers |
| memcpy |
copies one buffer to another |
| memmove |
moves one buffer to another |
| memset |
fills a buffer with a character |
| mktime |
returns the calendar version of a given
time |
| modf |
decomposes a number into integer and
fractional parts |
| perror |
displays a string version of the current
error to STDERR |
| pow |
returns a given number raised to another
number |
| printf |
write formatted output to
STDOUT |
| putc |
write a character to a stream |
| putchar |
write a character to
STDOUT |
| puts |
write a string to
STDOUT |
| qsort |
perform a quicksort |
| raise |
send a signal to the program |
| rand |
returns a pseudorandom number |
| realloc |
changes the size of previously allocated
memory |
| remove |
erase a file |
| rename |
rename a file |
| rewind |
move the file position indicator to the
beginning of a file |
| scanf |
read formatted input from
STDIN |
| setbuf |
set the buffer for a specific
stream |
| setjmp |
set execution to start at a certain
point |
| setlocale |
sets the current locale |
| setvbuf |
set the buffer and size for a specific
stream |
| signal |
register a function as a signal
handler |
| sin |
sine |
| sinh |
hyperbolic sine |
| sprintf |
write formatted output to a buffer |
| sqrt |
square root |
| srand |
initialize the random number
generator |
| sscanf |
read formatted input from a buffer |
| strcat |
concatenates two strings |
| strchr |
finds the first occurance of a character
in a string |
| strcmp |
compares two strings |
| strcoll |
compares two strings in accordance to
the current locale |
| strcpy |
copies one string to another |
| strcspn |
searches one string for any characters
in another |
| strerror |
returns a text version of a given error
code |
| strftime |
returns individual elements of the date
and time |
| strlen |
returns the length of a given
string |
| strncat |
concatenates a certain amount of
characters of two strings |
| strncmp |
compares a certain amount of characters
of two strings |
| strncpy |
copies a certain amount of characters
from one string to another |
| strpbrk |
finds the first location of any
character in one string, in another string |
| strrchr |
finds the last occurance of a character
in a string |
| strspn |
returns the length of a substring of
characters of a string |
| strstr |
finds the first occurance of a substring
of characters |
| strtod |
converts a string to a double |
| strtok |
finds the next token in a string |
| strtol |
converts a string to a long |
| strtoul |
converts a string to an unsigned
long |
| strxfrm |
converts a substring so that it can be
used by string comparison functions |
| system |
perform a system call |
| tan |
tangent |
| tanh |
hyperbolic tangent |
| time |
returns the current calendar time of the
system |
| tmpfile |
return a pointer to a temporary
file |
| tmpnam |
return a unique filename |
| tolower |
converts a character to lowercase |
| toupper |
converts a character to uppercase |
| ungetc |
puts a character back into a
stream |
| va_arg |
use variable length parameter
lists |
| vprintf,
vfprintf, and vsprintf |
write formatted output with variable
argument lists |