fgets

Reads at most count - 1 characters from the given file stream and stores them in the character array pointed to by str. Parsing stops if a newline character is found (in which case str will contain that newline character) or if end-of-file occurs. If bytes are read and no errors occur, writes a null character at the position immediately after the last character written to str.

[edit] Parameters

[edit] Return value

str on success, null pointer on failure.

If the end-of-file condition is encountered, sets the eof indicator on stream (see feof() ). This is only a failure if it causes no bytes to be read, in which case a null pointer is returned and the contents of the array pointed to by str are not altered (i.e. the first byte is not overwritten with a null character).

If the failure has been caused by some other error, sets the error indicator (see ferror() ) on stream. The contents of the array pointed to by str are indeterminate (it may not even be null-terminated).

[edit] Notes

POSIX additionally requires that fgets sets errno if a read error occurs.

Although the standard specification is unclear in the cases where count <= 1, common implementations do

• if count < 1, do nothing, report error,
• if count == 1,

• some implementations do nothing, report error,
• others read nothing, store zero in str[0], report success.

[edit] Example

#include <stdio.h>
#include <stdlib.h>
 
int main(void)
{
 FILE * tmpf = tmpfile ();
 fputs ("Alan Turing\n", tmpf);
 fputs ("John von Neumann\n", tmpf);
 fputs ("Alonzo Church\n", tmpf);
 
 rewind (tmpf);
 
 char buf[8];
 while (fgets(buf, sizeof buf, tmpf) != NULL )
 printf ("\"%s\"\n", buf);
 
 if (feof (tmpf))
 puts ("End of file reached");
}

"Alan Tu"
"ring
"
"John vo"
"n Neuma"
"nn
"
"Alonzo "
"Church
"
End of file reached

[edit] References

[edit] See also

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