{"items":[{"id":"680f47ec-2262-43c5-88c9-45f983760fd8","title":"UNIX-programming-programs-procs","slug":"unix-programming-programs-procs","contentHtml":"

A program is an executable file residing on disk in a directory.

#ProcandprocID
An executing instance of a program is called a process. Some OS use the term task for this process.
In UNIX systems every process has a unique numeric identifier called the process ID.
The process ID is always non-negativ integer (U64).

For example a process ID is look like this in UNIX based opearation systems:

When this programs runs, it calls the function 'getpid' to obtain its process ID.

If u want to print a process ID:

#include <apue.h>\n\nint main(void){\n\n    printf(\"This process ID is from %d\\n\", getpid());\n    exit(0);\n}\n\n// its return the process ID of this proc\n

#Proccontrol

There are three primary funcs to process control: 'fork', 'exec' and waitpid.

","contentJson":{"type":"doc","content":[{"type":"paragraph","content":[{"text":"A program is an executable file residing on disk in a directory.","type":"text"}]},{"type":"paragraph","content":[{"text":"#ProcandprocID","type":"text","marks":[{"type":"link","attrs":{"rel":"noopener noreferrer nofollow","href":"#ProcandprocID","class":"tag","title":null,"target":"_blank"}}]},{"type":"hardBreak"},{"text":"An executing instance of a program is called a process. Some OS use the term task for this process.","type":"text"},{"type":"hardBreak"},{"text":"In UNIX systems every process has a unique numeric identifier called the process ID.","type":"text"},{"type":"hardBreak"},{"text":"The process ID is always non-negativ integer (U64).","type":"text"}]},{"type":"paragraph","content":[{"text":"For example a process ID is look like this in UNIX based opearation systems:","type":"text"}]},{"type":"image","attrs":{"alt":null,"src":"/api/uploads/5aa49567-5839-4087-a865-e8715fd09421.webp","title":null,"width":"85%","height":null}},{"type":"paragraph","content":[{"text":"When this programs runs, it calls the function 'getpid' to obtain its process ID.","type":"text"}]},{"type":"paragraph","content":[{"text":"If u want to print a process ID:","type":"text"}]},{"type":"codeBlock","attrs":{"language":null},"content":[{"text":"#include \n\nint main(void){\n\n printf(\"This process ID is from %d\\n\", getpid());\n exit(0);\n}\n\n// its return the process ID of this proc\n","type":"text"}]},{"type":"paragraph","content":[{"text":"#Proccontrol","type":"text","marks":[{"type":"link","attrs":{"rel":"noopener noreferrer nofollow","href":"#Proccontrol","class":"tag","title":null,"target":"_blank"}}]}]},{"type":"paragraph","content":[{"text":"There are three primary funcs to process control: 'fork', 'exec' and waitpid. ","type":"text"}]},{"type":"paragraph"}]},"remote":false,"status":"published","publishAt":null,"language":null,"summary":null,"coverUrl":null,"bannerUrl":"/api/uploads/5aa49567-5839-4087-a865-e8715fd09421.webp","coverCredit":null,"createdAt":"2026-07-30T15:51:38.274Z","updatedAt":"2026-07-30T15:51:38.274Z","author":{"id":"edd8b60c-384b-477f-aac0-7466b542fcc3","username":"denis","displayName":"Voctl","avatarUrl":"/api/uploads/b5c8fbe5-ad5a-4f26-a29a-d8c91901e014.webp","remote":false},"tags":[{"slug":"c","name":"c"},{"slug":"larp","name":"larp"},{"slug":"lowlevel","name":"lowlevel"},{"slug":"recreational","name":"recreational"},{"slug":"unix","name":"unix"}],"likeCount":2,"liked":false,"commentCount":0,"recommendCount":0,"recommended":false,"recommendedBy":null}],"nextCursor":null}