src/sock.c:542:5: warning: conversion to 'long unsigned int' from 'int' may change the sign of the result

[subnut]

• My goal is: to make linux-libs on x86_64-musl (NOT glibc)

Environment

• mongoose version: 7.6
• Compiler/IDE and SDK: gcc version 10.2.1
• Target hardware/board: x86-64

Elephant in the room

src/sock.c: In function 'mg_iotest':
src/sock.c:542:5: warning: conversion to 'long unsigned int' from 'int' may change the sign of the result [-Wsign-conversion]
  542 |     if (FD(c) > maxfd) maxfd = FD(c);
      |     ^~~~~~
src/sock.c:542:5: warning: conversion to 'long unsigned int' from 'int' may change the sign of the result [-Wsign-conversion]
src/sock.c:545:7: warning: conversion to 'long unsigned int' from 'int' may change the sign of the result [-Wsign-conversion]
  545 |   }
      |       ^     
src/sock.c:545:7: warning: conversion to 'long unsigned int' from 'int' may change the sign of the result [-Wsign-conversion]
src/sock.c:556:49: warning: conversion to 'long unsigned int' from 'int' may change the sign of the result [-Wsign-conversion]
  556 |     c->is_writable = FD(c) != INVALID_SOCKET && FD_ISSET(FD(c), &wset);
      |                                                 ^~~~~~~~
src/sock.c:556:49: warning: conversion to 'long unsigned int' from 'int' may change the sign of the result [-Wsign-conversion]
src/sock.c:557:49: warning: conversion to 'long unsigned int' from 'int' may change the sign of the result [-Wsign-conversion]
  557 |   }
      |                                                 ^       
src/sock.c:557:49: warning: conversion to 'long unsigned int' from 'int' may change the sign of the result [-Wsign-conversion]

[subnut]

Ping @cpq

[cpq]

That's actually a musl's header problem.
See https://inbox.vuxu.org/musl/20200803174707.GF6949@brightrain.aerifal.cx/T/

Note: the error reporting is one line off. The real issue is on line 499: if you comment it out, the warning goes away. So the issue is with this line:

FD_SET(FD(c), &rset);