There appears to be an obscure bug that has somehow recently activated on ARMv6, non-FPU builds<\/s> of VLC for Android. This has been only observed on Android 2.1 and possibly on other Android 2.x platforms with ARMv6, non-FPU builds<\/s> Android 2.2. On the other hand, it works perfectly on an Android 4.0 on a NEON device (same code), so it is probably specific to Android 2.2 and 2.1 (not tested on 1.6).<\/p>\n
The obscure bug involves hanging during a fclose() call whilst being run inside a POSIX pthread_once thread. This obscure bug was causing hanging on startup of VLC for Android on an Android 2.1, no-FPU, no-NEON device<\/a>. Further testing with the Android emulator also revealed that the Android 2.1 and 2.2 emulator<\/strong> crashes too, suggesting a bionic bug (Android 2.3 works fine). Here is a condensed, VLC-neutral version of the code from VLC core that is specific to this problem, adapted from src\/posix\/linux_cpu.c<\/a>:<\/p>\n Interestingly, after debugging there are two ways to workaround this bug:<\/p>\n\r\n\/\/ arm-linux-androideabi-gcc --sysroot=\/opt\/android-ndk-r8\/platforms\/android-9\/arch-arm -I. -g -march=armv6j -mtune=arm1136j-s -msoft-float android.c -o android\r\n#include <stdio.h>\r\n#include <string.h>\r\n#include <pthread.h>\r\n#include <stdlib.h>\r\n\r\n\/* getdelim and getline courtesy of VLC's compat\/getdelim.c *\/\r\nssize_t getdelim(char**v1,size_t*v2,int v3,FILE*v4){char*A1=*v1;size_t A2=(A1 != NULL)?*v2:0;size_t A3 = 0;for(;;){if((A2 - A3) <= 2){A2=A2?(A2*2):256;A1=realloc(*v1,A2);if(A1 ==NULL)return-1;*v1=A1;*v2=A2;}int c=fgetc(v4);if(c==-1){if(A3==0||ferror(v4))return -1;break;}A1[A3++]=c;if(c==v3)break;}A1[A3]='\0';return A3;} ssize_t getline(char** a,size_t* b,FILE* c){return getdelim(a,b,'\\n',c);}\r\n\r\nstatic uint32_t cpu_flags = 0;\r\n\r\nstatic void vlc_CPU_init (void) {\r\n FILE *info = fopen ("\/proc\/cpuinfo", "rt");\r\n if (info == NULL) return;\r\n char *line = NULL;\r\n size_t linelen = 0;\r\n\t\/\/ ...irrelevant code skipped...\r\n while (getline (&line, &linelen, info) != -1) {\r\n \/\/ ...do stuff with the loop...\r\n }\r\n fclose(info); \/* hangs here *\/\r\n free(line);\r\n\t\/\/ ...parse and set cpu_flags...\r\n cpu_flags = 1;\r\n}\r\n\r\nunsigned vlc_CPU(void) {\r\n static pthread_once_t once = PTHREAD_ONCE_INIT;\r\n pthread_once (&once, vlc_CPU_init);\r\n \/\/vlc_CPU_init();\r\n return cpu_flags;\r\n}\r\n\r\nint main(void) {\r\n if(vlc_CPU() > 0)\r\n puts("Successful");\r\n else\r\n puts("Failure, or a.k.a. will never reach here");\r\n return 0;\r\n}\r\n<\/pre>\n\n