Change type of function pointer #66

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opened 2024-02-18 17:59:06 +00:00 by nitori · 3 comments

nitori commented

2024-02-18 17:59:06 +00:00

Owner

The return types of read(2) and write(2) are actually ssize_t and not int.
This causes a compilation error on clang, but just a warning on gcc.
I can't create a pull request so here's a diff:

diff --git a/src/dj.c b/src/dj.c
index d5bd59c..8a982fa 100644
--- a/src/dj.c
+++ b/src/dj.c
@@ -199,7 +199,7 @@ Io_fdopen(struct Io *io, char *fn){
  * be set to zero to indicate the seek occurred. */
 static int
 Io_fdseek(struct Io *io){
-       int (*op)(int, void *, size_t);
+       ssize_t (*op)(int, void *, size_t);

        if(!fdisstd(io->fd) && lseek(io->fd, io->seek, SEEK_SET) != -1)
                return -1;
@@ -209,7 +209,7 @@ Io_fdseek(struct Io *io){
                 * likewise, because the parameters to read or write are going to be
                 * the same either way, just use a function pointer to keep track of
                 * the intended operation. */
-               op = (int (*)(int, void *, size_t))&write;
+               op = (ssize_t (*)(int, void *, size_t))&write;
                /* Function pointer casts are risky; this works because the difference
                 * is in the second parameter and only that write(2) makes the buffer
                 * const whereas read(2) does not. To avoid even the slightest

The return types of `read(2)` and `write(2)` are actually `ssize_t` and not `int`. This causes a compilation error on clang, but just a warning on gcc. I can't create a pull request so here's a diff: ```diff diff --git a/src/dj.c b/src/dj.c index d5bd59c..8a982fa 100644 --- a/src/dj.c +++ b/src/dj.c @@ -199,7 +199,7 @@ Io_fdopen(struct Io *io, char *fn){ * be set to zero to indicate the seek occurred. */ static int Io_fdseek(struct Io *io){ - int (*op)(int, void *, size_t); + ssize_t (*op)(int, void *, size_t); if(!fdisstd(io->fd) && lseek(io->fd, io->seek, SEEK_SET) != -1) return -1; @@ -209,7 +209,7 @@ Io_fdseek(struct Io *io){ * likewise, because the parameters to read or write are going to be * the same either way, just use a function pointer to keep track of * the intended operation. */ - op = (int (*)(int, void *, size_t))&write; + op = (ssize_t (*)(int, void *, size_t))&write; /* Function pointer casts are risky; this works because the difference * is in the second parameter and only that write(2) makes the buffer * const whereas read(2) does not. To avoid even the slightest ```

trinity commented

2024-02-18 20:40:58 +00:00

Owner

I should just drop the function pointer magic and use an if - working around type differences there (on which this is further elaborated in the surrounding comments) has caused me enough grief as-is.

I should just drop the function pointer magic and use an `if` - working around type differences there (on which this is further elaborated in the surrounding comments) has caused me enough grief as-is.