The Open Group Base Specifications Issue 7
IEEE Std 1003.1-2008
Copyright © 2001-2008 The IEEE and The Open Group


fgets - get a string from a stream


#include <stdio.h>

char *fgets(char *restrict
s, int n, FILE *restrict stream);


[CX] [Option Start] The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional. This volume of POSIX.1-2008 defers to the ISO C standard. [Option End]

The fgets() function shall read bytes from stream into the array pointed to by s, until n-1 bytes are read, or a <newline> is read and transferred to s, or an end-of-file condition is encountered. The string is then terminated with a null byte.

[CX] [Option Start] The fgets() function may mark the last data access timestamp of the file associated with stream for update. The last data access timestamp shall be marked for update by the first successful execution of fgetc(), fgets(), fread(), fscanf(), getc(), getchar(), getdelim(), getline(), gets(), or scanf() using stream that returns data not supplied by a prior call to ungetc(). [Option End]


Upon successful completion, fgets() shall return s. If the stream is at end-of-file, the end-of-file indicator for the stream shall be set and fgets() shall return a null pointer. If a read error occurs, the error indicator for the stream shall be set, fgets() shall return a null pointer, [CX] [Option Start]  and shall set errno to indicate the error. [Option End]


Refer to fgetc .

The following sections are informative.


Reading Input

The following example uses fgets() to read each line of input. {LINE_MAX}, which defines the maximum size of the input line, is defined in the <limits.h> header.

#include <stdio.h>
char line[LINE_MAX];
while (fgets(line, LINE_MAX, fp) != NULL) {








fgetc , fopen , fread , fscanf , getc , getchar , getdelim , gets , ungetc

XBD <stdio.h>


First released in Issue 1. Derived from Issue 1 of the SVID.

Issue 6

Extensions beyond the ISO C standard are marked.

The prototype for fgets() is changed for alignment with the ISO/IEC 9899:1999 standard.

Issue 7

Austin Group Interpretation 1003.1-2001 #051 is applied, updating the list of functions that mark the last data access timestamp for update.

End of informative text.


return to top of page

UNIX ® is a registered Trademark of The Open Group.
POSIX ® is a registered Trademark of The IEEE.
Copyright © 2001-2008 The IEEE and The Open Group, All Rights Reserved
[ Main Index | XBD | XSH | XCU | XRAT ]