collect all common functions into separate library; add simple client example

examples/CMakeLists.txt

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+cmake_minimum_required(VERSION 3.20)
+
+include_directories(..)
+add_executable(ccd_client main.c)
+target_link_libraries(ccd_client ccdcapture usefull_macros)

examples/main.c

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+/*
+ * This file is part of the CCD_Capture project.
+ * Copyright 2023 Edward V. Emelianov <edward.emelianoff@gmail.com>.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * A simple example to take 8-bit images with default size and given exposition time.
+ * Works in `infinity` mode or requesting each file after receiving previous.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <usefull_macros.h>
+
+#include "socket.h"
+
+typedef struct{
+    char *sockname;     // UNIX socket name of command socket or port of local socket
+    int isun;           // command socket is UNIX socket instead of INET
+    int shmkey;         // shared memory (with image data) key
+    int infty;          // run in infinity loop (if not - run by requests)
+    int nframes;        // amount of frames to take
+    int help;           // show this help
+    double exptime;     // time of exposition in seconds
+} glob_pars;
+
+
+static glob_pars G = {
+    .shmkey = 7777777,
+    .nframes = 10
+};
+
+/*
+ * Define command line options by filling structure:
+ *  name    has_arg flag    val     type        argptr          help
+*/
+myoption cmdlnopts[] = {
+    {"sock",    NEED_ARG,   NULL,   's',    arg_string, APTR(&G.sockname),  "command socket name or port"},
+    {"isun",    NO_ARGS,    NULL,   'U',    arg_int,    APTR(&G.isun),      "use UNIX socket"},
+    {"shmkey",  NEED_ARG,   NULL,   'k',    arg_int,    APTR(&G.shmkey),    "shared memory (with image data) key (default: 7777777)"},
+    {"infty",   NO_ARGS,    NULL,   'i',    arg_int,    APTR(&G.infty),     "run in infinity capturing loop (else - request each frame)"},
+    {"nframes", NEED_ARG,   NULL,   'n',    arg_int,    APTR(&G.nframes),   "make series of N frames"},
+    {"exptime", NEED_ARG,   NULL,   'x',    arg_double, APTR(&G.exptime),   "set exposure time to given value (seconds!)"},
+    {"help",    NO_ARGS,    NULL,   'h',    arg_int,    APTR(&G.help),      "show this help"},
+};
+
+static cc_IMG *shimg = NULL, img = {0};
+
+static int refresh_img(){
+    if(!shimg) return FALSE;
+    static size_t imnumber = 0;
+    if(shimg->imnumber == imnumber) return FALSE;
+    imnumber = shimg->imnumber;
+    void *optr = img.data;
+    memcpy(&img, shimg, sizeof(img));
+    img.data = realloc(optr, img.bytelen);
+    memcpy(img.data, (uint8_t*)shimg + sizeof(cc_IMG), img.bytelen);
+    return TRUE;
+}
+
+int main(int argc, char **argv){
+    initial_setup();
+    parseargs(&argc, &argv, cmdlnopts);
+    if(G.help) showhelp(-1, cmdlnopts);
+    if(argc > 0){
+        WARNX("%d unused parameters:", argc);
+        for(int i = 0; i < argc; ++i)
+            printf("%4d: %s\n", i, argv[i]);
+    }
+    if(!G.sockname) ERRX("Point socket name or port");
+    int sock = cc_open_socket(FALSE, G.sockname, !G.isun);
+    if(sock < 0) ERR("Can't open socket %s", G.sockname);
+    shimg = cc_getshm(G.shmkey, 0);
+    if(!shimg) ERRX("Can't get shared memory segment");
+    int i = 0;
+    time_t oldtime = time(NULL);
+    double oldtimestamp = shimg->timestamp;
+    do{
+        time_t now = time(NULL);
+        if(now - oldtime > 5){
+            WARNX("No new images for 5 seconds");
+            break;
+        }
+        if(!refresh_img()){
+            usleep(1000);
+            continue;
+        }
+        ++i;
+        oldtime = now;
+        printf("Got image #%zd, size %dx%d, bitpix %d, time %g\n", img.imnumber, img.w, img.h, img.bitpix, img.timestamp-oldtimestamp);
+    }while(i < 10);
+    close(sock);
+    return 0;
+}