Re: [PATCH v3] getdents.2: Use appropriate types

Michael Kerrisk (man-pages)
2020-10-29T19:55:39Z

On 10/29/20 3:10 PM, Alejandro Colomar wrote:
> getdents():
> This function has no glibc wrapper.
> As such, we should use the same types the Linux kernel uses:
> Use 'long' as the return type.
>
> getdents64():
> The glibc wrapper uses:
> ssize_t getdents64(int, void *, size_t);
>
> Signed-off-by: Alejandro Colomar <colomar.6.4.3@gmail.com>

Thanks, Alex. Applied.

Cheers,

Michael

> ---
>
> Hi Michael,
>
> Sorry, I'm being a bit distracted these days :)
> It should be good enough now, I think.
>
> Cheers,
>
> Alex
>
> man2/getdents.2 | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/man2/getdents.2 b/man2/getdents.2
> index a187fbcef..ed3bb40b1 100644
> --- a/man2/getdents.2
> +++ b/man2/getdents.2
> @@ -33,14 +33,13 @@
> getdents, getdents64 \- get directory entries
> .SH SYNOPSIS
> .nf
> -.BI "int getdents(unsigned int " fd ", struct linux_dirent *" dirp ,
> +.BI "long getdents(unsigned int " fd ", struct linux_dirent *" dirp ,
> .BI " unsigned int " count );
> .PP
> .BR "#define _GNU_SOURCE" " /* See feature_test_macros(7) */"
> .B #include <dirent.h>
> .PP
> -.BI "int getdents64(unsigned int " fd ", struct linux_dirent64 *" dirp ,
> -.BI " unsigned int " count );
> +.BI "ssize_t getdents64(int " fd ", void *" dirp ", size_t " count );
> .fi
> .PP
> .IR Note :
> @@ -282,7 +281,8 @@ struct linux_dirent {
> int
> main(int argc, char *argv[])
> {
> - int fd, nread;
> + int fd;
> + long nread;
> char buf[BUF_SIZE];
> struct linux_dirent *d;
> char d_type;
> @@ -301,7 +301,7 @@ main(int argc, char *argv[])
>
> printf("\-\-\-\-\-\-\-\-\-\-\-\-\-\-\- nread=%d \-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\en", nread);
> printf("inode# file type d_reclen d_off d_name\en");
> - for (int bpos = 0; bpos < nread;) {
> + for (long bpos = 0; bpos < nread;) {
> d = (struct linux_dirent *) (buf + bpos);
> printf("%8ld ", d\->d_ino);
> d_type = *(buf + bpos + d\->d_reclen \- 1);
>

--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/