Environment Variables If you want to set a number of environment variables into your docker image (to be used within the containers) you can simply use env_file configuration option in your docker-compose.yml file. With that option, all the entries in the .env file will be set as the environment variables in image and hence into … Read more
From LSP (page 28): Yes, this function’s name is missing an e. Ken Thompson, the creator of Unix, once joked that the missing letter was his largest regret in the design of Unix.
Here’s a code example that demonstrates capturing multiple groups. You can see that group ‘0’ is the whole match, and subsequent groups are the parts within parentheses. Note that this will only capture the first match in the source string. Here’s a version that captures multiple groups in multiple matches. #include <stdio.h> #include <string.h> #include … Read more
In the area of “requires POSIX filesystem semantics” what is typically meant is: allows hierarchical file names and resolution (., .., …) supports at least close-to-open semantics umask/unix permissions, 3 filetimes 8bit byte support supports atomic renames on same filesystem fsync()/dirfsync() durability gurantee/limitation supports multi-user protection (resizing file returns 0 bytes not previous content) rename … Read more
POSIX threads (pthread) is not an implementation, it is a API specification (a standard, on paper, in english) of several functions whose name starts with pthread_ and which are defined in <pthread.h> header. POSIX is also a set of specifications. NPTL is now inside GNU Libc on Linux and is (or at least tries very … Read more
It’s there under “dot”. NAME dot – execute commands in the current environment SYNOPSIS . file [etc.]
New answer for old question. Rationale: updated tools. Using this free, open source library, one can parse into a std::chrono::time_point<system_clock, milliseconds>, which has the advantage over a tm of being able to hold millisecond precision. And if you really need to, you can continue on to the C API via system_clock::to_time_t (losing the milliseconds along … Read more
The idea is that you provide a mask in set, effectively a list of signals. The how argument says what you should do with the mask in set. You can either use SIG_BLOCK to block the signals in the set list, or SIG_UNBLOCK to unblock them. Neither of these changes the signals that aren’t set … Read more
ssize_t is defined in sys/types.h. Per the POSIX documentation: NAME sys/types.h – data types SYNOPSIS #include <sys/types.h> DESCRIPTION The header shall define at least the following types: … ssize_t Used for a count of bytes or an error indication.
POSIX 1003.1-2008 is now available on the web (all 3872 pages of it, in PDF and HTML). You have to register (free). I got to it from the Open Group Bookstore. See How to Portably scanf into a pid_t in C for my original answer that included this information.