c語言進程信息

㈠ 用c語言寫三個進程。 第一個進程輸入信息（例如字元串）第二個進程修改信息，第三個進程存到txt文本

聲明兩個char型數組，輸入兩個字元串存入a和b。用一個for循環依次比較a和b對應的字元，不同時結束比較，然後計算這兩個不同字元的差值輸出。代碼如下： #include "stdio.h"int main(int argc,char *argv[]){ char a[101],b[101],i; printf("Input 2 strings...\n"); scanf("%100s%100s",a,b);//輸入字元串並限制長度 for(i=0;a[i]==b[i] && (b[i] || a[i]);i++);//比較到不同字元或結束符 a[i] ? printf("\n'%c'",a[i]) : printf("\n'\\0'");//輸出a串與b串不同的字元 b[i] ? printf("-'%c'",b[i]) : printf("-'\\0'");//輸出-b串與a串不同的字元 printf(" = %d\n",a[i]-b[i]);//輸出a串與b串第一個不同字元的差值 return 0;} 運行樣例如下：

㈡ C語言創建進程

#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include<sys/wait.h>

intmain()
{
	for(intj=0;j<5;++j){
		intpid=fork();
		if(pid==0){//child
			printf("j:%d,pid:%d.
",j,getpid());
			exit(0);
		}elseif(pid<0){//error
			exit(-1);
		}
	}
	
	for(inti=0;i<5;++i){
		wait(NULL);
	}
	
	printf("End!
");
	
	return0;
}

㈢ 使用linux編寫C語言程序，如何才能得到進程信息和父進程信息

我覺得這個問題你應該從另外一個方向去考慮，既然b不需要a的資源，那麼就不要在fork之前打開這些資源。
你如，你原來的代碼是
fd
=
open(...);
...
...
fork();
...
...
你現在就應該改成
fork();
if
(parent)
{
......
fd
=
open();
.....
}
else
{
....
}
如果你是要在a進程打開資源，運行了一些東西，得到了足夠的信息才需要調用其他啊程序來做下一步內容，如果按照上面的方法就無法實現了話，你面對的實際是進程間同步和通信的問題。
解決方法也很簡單，隨便通過一種通信機制（signal，pipe，等等），等a進程獲得足夠信息後，再通知b進程執行。比如
a:
fork();
/*
below
code
are
running
in
parent,
a
*/
...
...
fd
=
open();
...
...
notify(b);
/*
use
kill,
send,
etc.
to
notify
child
task
b)
....
b:
wait();
/*
for
example,
while(1)
sleep();
*/
execlp(xxx);

㈣ c語言如何在進程中獲取出錯信息

1、可以使用strerror(errno)，這個返回errno錯誤代碼解釋，返回個字元串指針。

2、strerror 函數用來 從錯誤號碼 查 用英文表達的錯誤內容，返回指針，指向這段英文字元串。
char * strerror ( int errnum );
如果知道錯誤號，填入數值。
如果不知道錯誤號，那麼在出錯發生時，及時用 errno 的當前值 作參數，列印這段字元串。例如：

#include<stdio.h>
#include<errno.h>
intmain()
{
FILE*pFile;
pFile=fopen("unexist.ent","r");
if(pFile==NULL)
printf("pFileerror:%s
",strerror(errno));
return0;
}

㈤ c語言里什麼叫進程

對於代碼來說， 進程就是當前程序運行的載體。 也就是程序本身。
進程結束， 程序也就退出了。

所以 中止進程後， 當前程序所有代碼都不會執行。

㈥ 使用linux編寫C語言程序，如何才能得到進程信息和父進程信息

getpid()得到當前進程的pid， getppid()是得到父進程的pid

寫成語句就是
printf ( "My process ID is%d\n", getpid());
printf ( "My parent's process ID is%d\n", getppid());

記得要添加頭文件 #include <stdio.h>

㈦ 用C語言結構狀態描述進程式控制制塊的信息

以下來自linux內核2.6.35.7版本的代碼，在頭文件linux/sched.h中定義
struct task_struct {
volatile long state; /* -1 unrunnable, 0 runnable, >0 stopped */
void *stack;
atomic_t usage;
unsigned int flags; /* per process flags, defined below */
unsigned int ptrace;

int lock_depth; /* BKL lock depth */

#ifdef CONFIG_SMP
#ifdef __ARCH_WANT_UNLOCKED_CTXSW
int oncpu;
#endif
#endif

int prio, static_prio, normal_prio;
unsigned int rt_priority;
const struct sched_class *sched_class;
struct sched_entity se;
struct sched_rt_entity rt;

#ifdef CONFIG_PREEMPT_NOTIFIERS
/* list of struct preempt_notifier: */
struct hlist_head preempt_notifiers;
#endif

/*
* fpu_counter contains the number of consecutive context switches
* that the FPU is used. If this is over a threshold, the lazy fpu
* saving becomes unlazy to save the trap. This is an unsigned char
* so that after 256 times the counter wraps and the behavior turns
* lazy again; this to deal with bursty apps that only use FPU for
* a short time
*/
unsigned char fpu_counter;
#ifdef CONFIG_BLK_DEV_IO_TRACE
unsigned int btrace_seq;
#endif

unsigned int policy;
cpumask_t cpus_allowed;

#ifdef CONFIG_TREE_PREEMPT_RCU
int rcu_read_lock_nesting;
char rcu_read_unlock_special;
struct rcu_node *rcu_blocked_node;
struct list_head rcu_node_entry;
#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */

#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
struct sched_info sched_info;
#endif

struct list_head tasks;
struct plist_node pushable_tasks;

struct mm_struct *mm, *active_mm;
#if defined(SPLIT_RSS_COUNTING)
struct task_rss_stat rss_stat;
#endif
/* task state */
int exit_state;
int exit_code, exit_signal;
int pdeath_signal; /* The signal sent when the parent dies */
/* ??? */
unsigned int personality;
unsigned did_exec:1;
unsigned in_execve:1; /* Tell the LSMs that the process is doing an
* execve */
unsigned in_iowait:1;

/* Revert to default priority/policy when forking */
unsigned sched_reset_on_fork:1;

pid_t pid;
pid_t tgid;

#ifdef CONFIG_CC_STACKPROTECTOR
/* Canary value for the -fstack-protector gcc feature */
unsigned long stack_canary;
#endif

/*
* pointers to (original) parent process, youngest child, younger sibling,
* older sibling, respectively. (p->father can be replaced with
* p->real_parent->pid)
*/
struct task_struct *real_parent; /* real parent process */
struct task_struct *parent; /* recipient of SIGCHLD, wait4() reports */
/*
* children/sibling forms the list of my natural children
*/
struct list_head children; /* list of my children */
struct list_head sibling; /* linkage in my parent's children list */
struct task_struct *group_leader; /* threadgroup leader */

/*
* ptraced is the list of tasks this task is using ptrace on.
* This includes both natural children and PTRACE_ATTACH targets.
* p->ptrace_entry is p's link on the p->parent->ptraced list.
*/
struct list_head ptraced;
struct list_head ptrace_entry;

/* PID/PID hash table linkage. */
struct pid_link pids[PIDTYPE_MAX];
struct list_head thread_group;

struct completion *vfork_done; /* for vfork() */
int __user *set_child_tid; /* CLONE_CHILD_SETTID */
int __user *clear_child_tid; /* CLONE_CHILD_CLEARTID */

cputime_t utime, stime, utimescaled, stimescaled;
cputime_t gtime;
#ifndef CONFIG_VIRT_CPU_ACCOUNTING
cputime_t prev_utime, prev_stime;
#endif
unsigned long nvcsw, nivcsw; /* context switch counts */
struct timespec start_time; /* monotonic time */
struct timespec real_start_time; /* boot based time */
/* mm fault and swap info: this can arguably be seen as either mm-specific or thread-specific */
unsigned long min_flt, maj_flt;

struct task_cputime cputime_expires;
struct list_head cpu_timers[3];

/* process credentials */
const struct cred *real_cred; /* objective and real subjective task
* credentials (COW) */
const struct cred *cred; /* effective (overridable) subjective task
* credentials (COW) */
struct mutex cred_guard_mutex; /* guard against foreign influences on
* credential calculations
* (notably. ptrace) */
struct cred *replacement_session_keyring; /* for KEYCTL_SESSION_TO_PARENT */

char comm[TASK_COMM_LEN]; /* executable name excluding path
- access with [gs]et_task_comm (which lock
it with task_lock())
- initialized normally by setup_new_exec */
/* file system info */
int link_count, total_link_count;
#ifdef CONFIG_SYSVIPC
/* ipc stuff */
struct sysv_sem sysvsem;
#endif
#ifdef CONFIG_DETECT_HUNG_TASK
/* hung task detection */
unsigned long last_switch_count;
#endif
/* CPU-specific state of this task */
struct thread_struct thread;
/* filesystem information */
struct fs_struct *fs;
/* open file information */
struct files_struct *files;
/* namespaces */
struct nsproxy *nsproxy;
/* signal handlers */
struct signal_struct *signal;
struct sighand_struct *sighand;

sigset_t blocked, real_blocked;
sigset_t saved_sigmask; /* restored if set_restore_sigmask() was used */
struct sigpending pending;

unsigned long sas_ss_sp;
size_t sas_ss_size;
int (*notifier)(void *priv);
void *notifier_data;
sigset_t *notifier_mask;
struct audit_context *audit_context;
#ifdef CONFIG_AUDITSYSCALL
uid_t loginuid;
unsigned int sessionid;
#endif
seccomp_t seccomp;

/* Thread group tracking */
u32 parent_exec_id;
u32 self_exec_id;
/* Protection of (de-)allocation: mm, files, fs, tty, keyrings, mems_allowed,
* mempolicy */
spinlock_t alloc_lock;

#ifdef CONFIG_GENERIC_HARDIRQS
/* IRQ handler threads */
struct irqaction *irqaction;
#endif

/* Protection of the PI data structures: */
raw_spinlock_t pi_lock;

#ifdef CONFIG_RT_MUTEXES
/* PI waiters blocked on a rt_mutex held by this task */
struct plist_head pi_waiters;
/* Deadlock detection and priority inheritance handling */
struct rt_mutex_waiter *pi_blocked_on;
#endif

#ifdef CONFIG_DEBUG_MUTEXES
/* mutex deadlock detection */
struct mutex_waiter *blocked_on;
#endif
#ifdef CONFIG_TRACE_IRQFLAGS
unsigned int irq_events;
unsigned long hardirq_enable_ip;
unsigned long hardirq_disable_ip;
unsigned int hardirq_enable_event;
unsigned int hardirq_disable_event;
int hardirqs_enabled;
int hardirq_context;
unsigned long softirq_disable_ip;
unsigned long softirq_enable_ip;
unsigned int softirq_disable_event;
unsigned int softirq_enable_event;
int softirqs_enabled;
int softirq_context;
#endif
#ifdef CONFIG_LOCKDEP
# define MAX_LOCK_DEPTH 48UL
u64 curr_chain_key;
int lockdep_depth;
unsigned int lockdep_recursion;
struct held_lock held_locks[MAX_LOCK_DEPTH];
gfp_t lockdep_reclaim_gfp;
#endif

/* journalling filesystem info */
void *journal_info;

/* stacked block device info */
struct bio_list *bio_list;

/* VM state */
struct reclaim_state *reclaim_state;

struct backing_dev_info *backing_dev_info;

struct io_context *io_context;

unsigned long ptrace_message;
siginfo_t *last_siginfo; /* For ptrace use. */
struct task_io_accounting ioac;
#if defined(CONFIG_TASK_XACCT)
u64 acct_rss_mem1; /* accumulated rss usage */
u64 acct_vm_mem1; /* accumulated virtual memory usage */
cputime_t acct_timexpd; /* stime + utime since last update */
#endif
#ifdef CONFIG_CPUSETS
nodemask_t mems_allowed; /* Protected by alloc_lock */
int mems_allowed_change_disable;
int cpuset_mem_spread_rotor;
int cpuset_slab_spread_rotor;
#endif
#ifdef CONFIG_CGROUPS
/* Control Group info protected by css_set_lock */
struct css_set *cgroups;
/* cg_list protected by css_set_lock and tsk->alloc_lock */
struct list_head cg_list;
#endif
#ifdef CONFIG_FUTEX
struct robust_list_head __user *robust_list;
#ifdef CONFIG_COMPAT
struct compat_robust_list_head __user *compat_robust_list;
#endif
struct list_head pi_state_list;
struct futex_pi_state *pi_state_cache;
#endif
#ifdef CONFIG_PERF_EVENTS
struct perf_event_context *perf_event_ctxp;
struct mutex perf_event_mutex;
struct list_head perf_event_list;
#endif
#ifdef CONFIG_NUMA
struct mempolicy *mempolicy; /* Protected by alloc_lock */
short il_next;
#endif
atomic_t fs_excl; /* holding fs exclusive resources */
struct rcu_head rcu;

/*
* cache last used pipe for splice
*/
struct pipe_inode_info *splice_pipe;
#ifdef CONFIG_TASK_DELAY_ACCT
struct task_delay_info *delays;
#endif
#ifdef CONFIG_FAULT_INJECTION
int make_it_fail;
#endif
struct prop_local_single dirties;
#ifdef CONFIG_LATENCYTOP
int latency_record_count;
struct latency_record latency_record[LT_SAVECOUNT];
#endif
/*
* time slack values; these are used to round up poll() and
* select() etc timeout values. These are in nanoseconds.
*/
unsigned long timer_slack_ns;
unsigned long default_timer_slack_ns;

struct list_head *scm_work_list;
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
/* Index of current stored address in ret_stack */
int curr_ret_stack;
/* Stack of return addresses for return function tracing */
struct ftrace_ret_stack *ret_stack;
/* time stamp for last schele */
unsigned long long ftrace_timestamp;
/*
* Number of functions that haven't been traced
* because of depth overrun.
*/
atomic_t trace_overrun;
/* Pause for the tracing */
atomic_t tracing_graph_pause;
#endif
#ifdef CONFIG_TRACING
/* state flags for use by tracers */
unsigned long trace;
/* bitmask of trace recursion */
unsigned long trace_recursion;
#endif /* CONFIG_TRACING */
#ifdef CONFIG_CGROUP_MEM_RES_CTLR /* memcg uses this to do batch job */
struct memcg_batch_info {
int do_batch; /* incremented when batch uncharge started */
struct mem_cgroup *memcg; /* target memcg of uncharge */
unsigned long bytes; /* uncharged usage */
unsigned long memsw_bytes; /* uncharged mem+swap usage */
} memcg_batch;
#endif
};

㈧ 任意寫一個程序，將程序的進程信息列印出來（即像任務管理器一樣列印）C語言實現

#include <stdlib.h>

void main()
{
system("tasklist");
system("pause");
}

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