NAME
fgets — get a
string from a stream
SYNOPSIS
#include
<stdio.h>
char *fgets(char *restrict s, int n, FILE *restrict stream);
DESCRIPTION
[CX] 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 IEEE Std 1003.1-2001 (“POSIX.1”) defers to the ISO C standard.
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] The fgets ()
function may mark the st_atime field of the file
associated with stream for update. The
st_atime field shall be marked for update by the first
successful execution of fgetc(3),
fgets (), fgetwc(3),
fgetws(3), fread(3),
fscanf(3), getc(3),
getchar(3), gets(3), or
scanf(3) using stream that returns data
not supplied by a prior call to ungetc(3) or
ungetwc(3).
RETURN VALUE
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] and shall set
errno to
indicate the error.
ERRORS
Refer to fgetc(3) .
EXAMPLES
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) {
...
}
...
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
fopen(3) , fread(3) , gets(3) , the Base Definitions volume of IEEE Std 1003.1-2001 (“POSIX.1”), <stdio.h>
CHANGE HISTORY
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
(“ISO C99”) standard.
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