- fabs(), fabsf()
Compute the absolute value of a double number
- fcfgopen()
Open a configuration file
- fchdir()
Change the working directory
- fchmod()
Change the permissions for a file
- fchown()
Change the user ID and group ID of a file
- fclose()
Close a stream
- fcloseall()
Close all open stream files
- fcntl()
Provide control over an open file
- fdatasync()
Synchronize file data
- fdopen()
Associate a stream with a file descriptor
- feof()
Test a stream's end-of-file flag
- ferror()
Test a stream's error flag
- fflush()
Flush the buffers for a stream
- ffs()
Find the first bit set in a bit string
- fgetc()
Read a character from a stream
- fgetchar()
Read a character from stdin
- fgetpos()
Get the current position of a stream
- fgets()
Read a string of characters from a stream
- fgetspent()
Get an entry from the shadow password database
- fgetwc()
Read a wide character from a stream
- fgetws()
Read a string of wide characters from a stream
- fileno()
Return the file descriptor for a stream
- flink()
Assign a pathname to a file descriptor
- flock()
Apply or remove an advisory lock on an open file
- flockfile()
Acquire ownership of a file
- floor(), floorf()
Round down a value to the next integer
- flushall()
Flush all input/output buffers
- fmod(), fmodf(), fmodl()
Compute a residue, using floating-point modular arithmetic
- fnmatch()
Check to see if a file or path name matches a pattern
- fopen(), fopen64()
Open a file stream
- fork()
Create a new process
- forkpty()
Create a new process operating in a pseudo-tty
- fp_exception_mask()
Get or set the current exception mask
- fp_exception_value()
Get the value of the current exception registers
- fp_precision()
Set or get the current precision
- fp_rounding()
Set or get the current rounding
- fp_setenv()
Set the floating point environment
- fpathconf()
Return the value of a configurable limit associated with a file
- fprintf()
Write output to a stream
- fputc()
Write a character to a stream
- fputchar()
Write a character to stdout
- fputs()
Write a string to an output stream
- fputwc()
Write a wide character to a stream
- fputws()
Write a wide-character string to an output stream
- fread()
Read elements of a given size from a stream
- free()
Deallocate a block of memory
- freeaddrinfo()
Free a list of address information structures
- freeifaddrs()
Free a network interface address
- freopen(), freopen64()
Reopen a stream
- frexp(), frexpf()
Break a floating-point number into a normalized fraction and an integral power of 2
- fscanf()
Scan input from a stream
- fseek(), fseeko(), fseeko64()
Change the current position of a stream
- fsetpos()
Set the current position of a file
- fstat(), fstat64()
Get file information, given a file description
- fstatvfs(), fstatvfs64()
Get filesystem information, given a file descriptor
- fsync()
Synchronize the file state
- ftell(), ftello(), ftello64()
Return the current position of a stream
- ftime()
Get the current time
- ftruncate(), ftruncate64()
Truncate a file
- ftrylockfile()
Acquire ownership of a file, without blocking
- ftw(), ftw64()
Walk a file tree
- funlockfile()
Release ownership of a file
- futime()
Record the modification time for a file
- fwide()
Set or get the stream orientation
- fwprintf()
Write wide-character output to a stream
- fwrite()
Write elements to a file
- fwscanf()
Scan wide-character input from a stream