I want to use setenv() for data transfer as follows:
First, I convert an int to string, and then set a variable in a process, for example:
setenv(TEST, test, 1)
where TEST is the name of the environment variable, test is the converted numeric string, and 1 means that it can be overwritten.
Then, in the child process fork, I can get the string test corresponding to this variable through getenv, and then through atoi() into the corresponding data, so as to complete the data transfer I need.
Now, I want to implement data transfer between processes, but the typical three-way pipe, named pipe, and shared memory approach is too expensive and I just need to pass a single number, whereas setenv() and getenv() seem to pass only between the same process.
So, I wonder if there are any other ways to implement content transfer between processes besides the three typical process communication methods. This transfer only needs to be executed once and is one-way. How to set it up if setenv() is used?