I'm trying to write a program that uses read/write locks and would like to install the man pages for this type of lock.
I already have installed the packages
Could you please tell me the package that installs them or at least how to locate it?
Thank you very much in advance.
On Linux (two kinds of) locks are implemented in flock(2) and in fcntl(2).
As you already have installed manpages-dev both are available with man 2 flock and man 2 fcntl.
In case you are talking about POSIX threads locking (per the tag), POSIX additional manpages are available in manpages-posix-dev, in the non-free packages section, and thus appear to not be available through usual online Debian manpages links. From the package contents, this should be what you're looking for once installed:
pthread_rwlock_destroy.3posix
pthread_rwlock_rdlock.3posix
pthread_rwlock_timedrdlock.3posix
pthread_rwlock_timedwrlock.3posix
pthread_rwlock_tryrdlock.3posix
pthread_rwlock_trywrlock.3posix
pthread_rwlock_unlock.3posix
pthread_rwlock_wrlock.3posix
pthread_rwlockattr_destroy.3posix
pthread_rwlockattr_getpshared.3posix
pthread_rwlockattr_init.3posix
pthread_rwlockattr_setpshared.3posix
grep pthread_rwlock_rdlock /usr/include/pthreads.h => extern int pthread_rwlock_rdlock (pthread_rwlock_t *__rwlock). Also readelf -Ws /lib/x86_64-linux-gnu/libpthread.so.0 |grep pthread_rwlock_rdlock's output probably tells it exists "only" since glibc 2.2.5 released in 2002.
pthread_cancel are available both in section 3posix and section 3, but other are not simply because they were never "translated", not because the feature doesn't exist. Beside I addressed your question as it was written