OpenSolaris

Currently, _file in /usr/include/stdio.h is declared as an 
	unsigned char, which limits the number of file descriptors
	per process to 256 (2^8 = 256).  ISV's such as Sybase need
	to have that limit increased to 2048 for user connections
	to their database server.  Therefore, _file should be de-
	clared as an unsigned long instead of an unsigned char.

The description field as copied from bug report 1212385 follows:

Although the limit for file descriptors is 1024, you cannot open more than 256 fd's
using stdio.h. _file is declared as an unsigned char in /usr/include/stdio.h which
restricts the access to file descriptors to 256.

Reproduce by compiling and running the following program:

#include <stdio.h>

main()
{
       	FILE *fd;
       	int i;
       	char buf[10];

       	printf("Could not open ");
       	for(i=3; i < 1024; i++)
       	{
                sprintf(buf, "xx%d", i);
                fd = fopen(buf, "w"); 
                if (fd <= (FILE *)0)
                {
                       	printf("%d ",i);
                }
       	}
       	printf("\\n");
}



1) Documentation bug: man page for fopen() needs to directly acknowledge its
limitation to file descriptors 0-255 or at least direct the user to the stdio
man page for information about limitations.

2) Code bug: fopen() provides no identification of error when it hits the
above limitation:
errono is set to 0 when fopen() fails.

N/A

N/A