Control flow is the order in which a program executes statements and functions. A function call temporarily suspends the caller, transfers execution to the called function, and resumes the caller when a return is encountered. section 2.4.3 section 17.0
A call-and-return path
A small program follows this path: platform startup calls main; main calls printf; printf returns to main; main returns EXIT_SUCCESS to the startup routine. The transfers between these functions form the program’s visible control flow. section 2.4.3
Readable C makes the path through execution apparent:
- Structure statements in visually distinct {} blocks linked by comprehensive control statements. section 10.2
- Keep control flow obvious rather than burying break, continue, return, or goto inside complicated nested conditionals and loops. section 10.2
- Treat unusual, densely composed controlling expressions as another source of obscurity and subtle bugs. section 10.2
A basic block is a maximal sequence of statements that executes unconditionally from its first statement to its last. Blocks are joined by if/else and loop structures; return, goto, jump labels, certain case boundaries, and special-control-flow functions end them. section 17.0
Trace the transfer of execution among startup code, main, and printf in a small C program. section 2.4.3
