putty: Fails to compile on GCC 14 (error: passing argument 1 of ‘next_int’ from incompatible pointer type [-Wincompatible-pointer-types])

[Christopher Fore]

hen attempting to build the client using GCC 14, the following error (and warnings) occur:

unix/uxsftp.c: In function ‘read_from_file’:
unix/uxsftp.c:224:48: error: passing argument 1 of ‘next_int’ from incompatible pointer type [-Wincompatible-pointer-types]

224 | f->buffer_ = f->memory_ + next_int(&p);

| ^{~
| |
| const char}

In file included from ./putty.h:2437,

from unix/uxsftp.c:17:

./fzsftp.h:31:28: note: expected ‘char ’ but argument is of type ‘const char ’

31 | uintptr_t next_int(char s);

|

unix/uxsftp.c:225:43: error: passing argument 1 of ‘next_int’ from incompatible pointer type [-Wincompatible-pointer-types]

225 | f->remaining_ = (int)next_int(&p);

| ^{~
| |
| const char}

./fzsftp.h:31:28: note: expected ‘char ’ but argument is of type ‘const char ’

31 | uintptr_t next_int(char s);

|

unix/uxsftp.c:227:15: warning: passing argument 1 of ‘safefree’ discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]

227 | sfree(s);

|

In file included from ./misc.h:9,

from ./putty.h:10:

./puttymem.h:21:15: note: expected ‘void *’ but argument is of type ‘const char *’

21 | void safefree(void *);

| ^~

Patching the warning and error above results in another warning:

sftp.c: In function ‘sftp_alloc_request’:
sftp.c:138:18: warning: unused variable ‘i’ [-Wunused-variable]

138 | unsigned i = low + 1 + REQUEST_ID_OFFSET;

|

sftp.c: In function ‘fxp_got_status’:
sftp.c:220:11: warning: passing argument 1 of ‘safefree’ discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]

220 | sfree(fxp_error_message);

|

In file included from misc.h:9,

from sftp.c:11:

puttymem.h:21:15: note: expected ‘void *’ but argument is of type ‘const char *’

21 | void safefree(void *);

| ^~

sftp.c: In function ‘fxp_internal_error’:
sftp.c:262:11: warning: passing argument 1 of ‘safefree’ discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]

262 | sfree(fxp_error_message);

|

puttymem.h:21:15: note: expected ‘void *’ but argument is of type ‘const char *’

21 | void safefree(void *);

| ^~

The attached patch should correct these by removing the const attribute.

[Tim Kosse]

GCC 14 isn't release yet. Please report regressions in development builds of GCC to the GCC developers.

[Christopher Fore]

Replying to Tim Kosse:

GCC 14 isn't release yet. Please report regressions in development builds of GCC to the GCC developers.

This isn't a regression in GCC, rather they are simply being more strict about enforcing C99. Gentoo's been tracking C99 issues for about a year now if you'd like to look into it, here's their tracker:

​https://bugs.gentoo.org/870412

[Sam James]

GCC 14 will make several warnings error by default, see ​https://wiki.gentoo.org/wiki/Modern_C_porting. It's not a GCC bug.