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| author | Gregory Nutt <gnutt@nuttx.org> | 2014-11-29 17:39:40 -0600 |
|---|---|---|
| committer | Gregory Nutt <gnutt@nuttx.org> | 2014-11-29 17:39:40 -0600 |
| commit | ec9c929ff00c07df0e667b68bec285e1b02d8445 (patch) | |
| tree | c95e220e83a61be3139566acb5797528e678d6a8 /nuttx/libc/Kconfig | |
| parent | 833c0dc354e48f3c4de7aa938092e98f4ef8d980 (diff) | |
| download | px4-nuttx-ec9c929ff00c07df0e667b68bec285e1b02d8445.tar.gz px4-nuttx-ec9c929ff00c07df0e667b68bec285e1b02d8445.tar.bz2 px4-nuttx-ec9c929ff00c07df0e667b68bec285e1b02d8445.zip | |
Updated comments
Diffstat (limited to 'nuttx/libc/Kconfig')
| -rw-r--r-- | nuttx/libc/Kconfig | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/nuttx/libc/Kconfig b/nuttx/libc/Kconfig index b49b92e31..5ea546aa9 100644 --- a/nuttx/libc/Kconfig +++ b/nuttx/libc/Kconfig @@ -76,7 +76,20 @@ config LIBC_IOCTL_VARIADIC WARNING: Use of this option could cause subtle system errors is the third argument is omitted or if the sizeof the thread argument - is anything other than sizeof (unsigned long). + is anything other than sizeof (unsigned long). Most small integers + will be promoted to 'int'. The following assertion appears in ioctl(): + + DEBUGASSERT(sizeof(int) == sizeof(unsigned long) && + sizeof(FAR void *) == sizeof(unsigned long)); + + Do not enable this option if the above is not true. 32-bit ARM + should pass this test with all three types having sizeof(type) == 4 + bytes. 'float' should also be tested. But 'long long' and 'double' + are out of the question! Don't event try to pass them. + + And what will happen if no third argument is passed? In most cases, + this should just result in a garbage value for arg. But you may + discover cases where something worse happens! config LIB_RAND_ORDER int "Order of the random number generate" |